Photosynthesis Quiz 6

Photosynthesis

light energy is converted to chemical energy, stored in organic compounds (often sugars)- occurs in photoautotrophs (plants, some algae, cyanobacteria)

Photosynthesis Equation

Energy+ 6 CO₂+ 6 H₂O —> 6 C₆H₁₂O_{6 +} 6 O₂

Plant structures used in photosynthesis

• stomata

• chloroplasts

• thylakoid

• stroma

Stomata

small openings in leaves that allow far diffusion of CO₂, H₂O, O₂

Chloroplasts

organelles within plant cells- site of photosynthesis 

Thylakoid

membrane-bound sacs within the chloroplasts that are the site of photon capture, the ETC, and ATP synthase

Stroma

fluid within chloroplasts surrounding the thylakoid membrane- site of carbon fixation and reduction of CO₂ into sugar 

Stages of Photosynthesis 

• light reactions (stage 1)

• carbon fixation and reduction rxns (stage 2)

Light Reactions

• occur in thylakoid membranes in chloroplasts

• sun energy harnessed into series of redox rxns involving splitting of H2O & chemiosmosis to create ATP & NADPH

Light Rxns Inputs

6H2O, NADP, light energy, 18ADP + Pi

Light Rxns Outputs

6O2, NADPH, 18 ATP

Carbon Fixation and Reduction Rxns (Calvin Cycle)

• takes place on stroma of chloroplasts

• uses ATP & NADPH created in 1st stage to perform carbon fixation & redox rxns to convert CO₂ to sugars

Carbon Fixation Inputs

6CO2, NADPH, 18 ATP

Carbon Fixation Outputs

C6H12O6, 6H2O, NADP, 18 ADP + Pi

CO₂

limiting reactant because without it, the whole cycle cannot happen

NADP⁺

a molecule that HAS to be regenerated (cannot happen when CO₂ is limited and when the sun sets)

CO₂ is ______ to C₆H₁₂O₆

reduced

Reduction of CO₂ to glucose is coupled to ____

oxidation of NADPH to NADP⁺

NADPH is ____ to NADP⁺

oxidized 

NADP⁺ is ____ to NADPH

reduced

Reduction of NADP+ to NADPH is coupled to _______

oxidation of water to oxygen

H₂O is _____ to O₂

oxidized 

_____ powers oxidation of water

sunlight

ADP is _______ to ATP

photophosphorylated

ATP is ______ to ADP

hydrolyzed

H₂O —> O₂

light rxns

C₆H₁₂O₆ —→ CO₂

carbon fixation rxn

ATP gets low

amount of NADP+ gets low and oxidation of NADPH gets delayed